\documentclass{article}
 
\usepackage[pdftex,active,tightpage]{preview}
\usepackage{tikz}
\usetikzlibrary{snakes}
\usetikzlibrary{arrows}
\makeatletter
 
\begin{document}
\begin{preview}
	%%
	\begin{tikzpicture}[scale=0.6]
				\draw[fill=orange!70!black, fill opacity=0.3] (0,0) circle (4);
				
				% \draw (0,0) circle (3.5);
				\draw[fill=red, fill opacity=0.5] (0,0) circle (3.5);
				
				
				\end{tikzpicture}
				%%
\end{preview}
\end{document}